Heretofore, in a high pressure fuel pump and the like, a pulsation damper is known in which a diaphragm provided on a low pressure fuel passage supplying fuel to a pressure chamber within a housing body is configured to absorb and reduce pulsation of a fluid introduced to the pressure chamber through a suction passage (refer for example to Patent Literature 1).
According to such conventional pulsation damper, the diaphragm is formed through pressing, such that a protrusion is formed in one direction of a metal plate formed of stainless steel or the like, and such that a ceiling portion (center portion) of the protrusion forms a flat surface parallel to a flange formed on an outer circumference of the diaphragm.
Then, a whole circumference of the diaphragm is welded to a predetermined flat plate (metal plate), or a flat plate is sandwiched between two diaphragms, and the whole circumference of the metal plate and the diaphragms are welded, or the two diaphragms are directly arranged in opposing relationship without providing a metal plate, and the whole circumference thereof is welded, to form the pulsation damper.
At this time, inert gas of helium or nitrogen is filled under a predetermined pressure and sealed in the space confined by the diaphragm and the metal plate, or the space confined by the two diaphragms.